Smoking product, method for producing said smoking product, and method for distinguishing granular activated carbon

ABSTRACT

Provided are: a smoking product that has a tobacco rod and a filter comprising granular activated carbon, wherein the lightness L* value of said granular activated carbon in the CIE Lab color space is 11.50-19.00 and the acetone adsorption capacity is 29.0-41.0% percentage by mass; a method for producing said smoking product; and a method for distinguishing granular activated carbon.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No. PCT/JP2018/038867, filed on Oct. 18, 2018, which is hereby expressly incorporated by reference into the present application.

TECHNICAL FIELD

The present invention relates to a smoking product including a granular activated carbon in a filter, a method for producing the smoking product, and a method for distinguishing a granular activated carbon.

BACKGROUND ART

A technique in which a colored material is included in a tobacco smoke filter has been known as means for preventing forgery of smoking products (Patent document 1). Patent document 1 discloses a technique relating to a tobacco smoke filter including a particulate adsorbent (e.g., granular activated carbon) colored in red, blue, white, yellow, green, or the like by being coated with a colored polymer material.

Non patent document 1 discloses an influence on the adsorptive power of specific components in smoke and the tobacco smoke taste exerted by the type and quality of activated carbon included in a filter of smoking products. Specifically, Non patent document 1 discloses that the favorable type of activated carbon included in a filter of smoking products is a coconut shell activated carbon and that, in terms of quality, the activated carbon favorably has a high filling density, contains a small amount of inorganic component, and has an acetone adsorptive power of less than 30%. It is also disclosed that the activated carbon having a high acetone adsorptive power has high adsorption efficacy of all volatile organic substances.

CITATION LIST Patent Document

Patent document 1: Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2010-527599

Non Patent Document

Non patent document 1: N. Ishizaki, “Activated Carbon Guidebook-Second edition-” Edited by H. Yanai, Nikkan Kogyo Shimbun, Ltd., Jul. 27, 1996

SUMMARY OF THE INVENTION Technical Problems to be Solved by the Invention

It is desirable that unauthorized products such as “forgeries” and “smuggled articles” of smoking products, which have posed a serious problem in recent years, can be distinguished from authorized products. That is, it is desirable that the authenticity can be determined.

In the invention disclosed in Patent document 1, a particulate adsorbent such as colored activated carbon particles is contained, and therefore the authenticity can be determined from the outer appearance of activated carbon. However, the change in specifications in which activated carbon particles, which are originally black particles, are colored in red, blue, white, yellow, green, or the like can be easily recognized by users of smoking products. This may interfere with conventional smoking of users.

In the art, the activated carbon added to a filter generally has an acetone adsorption capacity of less than 30% in terms of mass fraction.

The present invention provides a smoking product including, in a filter, a granular activated carbon that has an acetone adsorption capacity higher than or equal to that of known granular activated carbons and that allows determination of the authenticity of smoking products, and also provides a method for producing the smoking product.

Means for Solving the Problems

As a result of thorough studies conducted by the present inventor, the present inventor has found that the above object can be achieved by using a smoking product that includes a tobacco rod portion and a filter portion including a granular activated carbon, wherein the granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less in the CIE Lab colorimetric system and an acetone adsorption capacity of 29.0% or more and 41.0% or less in terms of mass fraction. Thus, the present invention has been made.

That is, the present invention is as follows.

-   [1] A smoking product comprising a tobacco rod portion and a filter     portion including a granular activated carbon, wherein the granular     activated carbon has a lightness L* of 11.50 or more and 19.00 or     less in a CIE Lab colorimetric system and an acetone adsorption     capacity of 29.0% or more and 41.0% or less in terms of mass     fraction. -   [2] The smoking product according to [1], wherein the granular     activated carbon has a color difference ΔE of 14.00 or more and     21.50 or less in the CIE Lab colorimetric system. -   [3] The smoking product according to [1] or [2], wherein the     granular activated carbon is a granular coconut shell activated     carbon. -   [4] A method for producing a smoking product comprising a tobacco     rod portion and a filter portion including a granular activated     carbon, the method comprising a step of providing a granular     activated carbon having a lightness L* of 11.50 or more and 19.00 or     less in a CIE Lab colorimetric system and a step of adding the     provided granular activated carbon to the filter portion. -   [5] The method for producing a smoking product according to [4],     wherein in the providing step, a granular activated carbon having a     lightness L* of 11.50 or more and 19.00 or less and also having a     color difference ΔE of 14.00 or more and 21.50 or less in a CIE     colorimetric system is provided. -   [6] The method for producing a smoking product according to [4] or     [5], wherein the granular activated carbon has an acetone adsorption     capacity of 29.0% or more and 41.0% or less in terms of mass     fraction. -   [7] The method for producing a smoking product according to any one     of [4] to [6], wherein the granular activated carbon is a granular     coconut shell activated carbon. -   [8] A method for distinguishing a granular activated carbon added to     a smoking product filter, the method comprising: a step of     numerically expressing a color of the granular activated carbon in a     CIE Lab colorimetric system; and a step of sorting, as the granular     activated carbon added to the smoking product filter, a granular     activated carbon having a lightness L* of 11.50 or more and 19.00 or     less in the CIE Lab colorimetric system. -   [9] The method according to [8], wherein in the sorting step, a     granular activated carbon having a lightness L* of 11.50 or more and     19.00 or less and also having a color difference ΔE of 14.00 or more     and 21.50 or less in the CIE Lab colorimetric system is sorted.

Advantageous Effects of Invention

According to the present invention, there can be provided a smoking product including, in a filter, a granular activated carbon which has an acetone adsorption capacity higher than or equal to that of known granular activated carbons and with which the determination of the authenticity of smoking products can be easily performed, a method for producing the smoking product, and a method for providing the granular activated carbon.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a photograph illustrating the outer appearance of granular coconut shell activated carbons in Example 2 and Comparative Example 3.

DESCRIPTION OF EMBODIMENTS

Hereafter, the present invention will be described in detail with reference to embodiments, examples, and the like. The present invention is not limited to the following embodiments, examples, and the like, and any modification can be made without departing from the spirit of the present invention.

<Smoking Product of the Present Invention>

The smoking product of the present invention may have a publicly known configuration except for a granular activated carbon added to a filter portion. For example, the smoking product may include a tobacco rod portion obtained by wrapping a typical tobacco filler such as shredded tobacco with a tobacco wrapping paper and a filter portion attached to one end of the tobacco rod portion.

A tobacco leaf raw material that is a raw material for shredded tobacco or the like included in the tobacco rod portion may be a shredded tobacco leaf raw material or an unshredded tobacco leaf raw material. For the tobacco leaf raw material, either a mesophyll portion (lamina) or a vein portion (midrib) obtained by separating tobacco leaves may be used, or a tobacco stem portion that is not a tobacco leaf portion may be contained. The tobacco leaf raw material may be a raw material shredded so as to have a shredding width of 0.1 to 2.0 mm. The tobacco leaf varieties may be main varieties such as yellow varieties, burley varieties, native varieties, and orient varieties, or fermented leaves using the foregoing.

The water content of a typical tobacco filler such as shredded tobacco included in the tobacco rod portion is not particularly limited, and may be 10 to 15 wt % and is preferably 11 to 13 wt %. At such a water content, the occurrence of a stain on the wrapping paper is suppressed and the machinability during the production of the smoking product is improved.

The outer surface of the filter portion may be wrapped with a tipping paper with a filter wrapper and a shaping paper disposed inside the tipping paper, which serve as a filter wrapping paper. Wrapping with a filter wrapper will be described below in detail.

The filter portion is constituted by one or more filter sections, and a publicly known material can be appropriately used for any of the filter sections. For example, acetate tow can be used as a material. The single yarn fineness, total fineness, and sectional shape of the acetate tow are not particularly limited.

In any of materials, adjustment of airflow resistance and addition of additives (e.g., publicly known adsorbents, flavors, and flavor retention materials) can be appropriately designed.

The filter wrapping paper is used to wrap the outer surface of a filter for publicly known smoking products, and is a collective term for tipping paper, shaping paper, and filter wrapper. Herein, the filter wrapper is used to achieve cylindrical wrapping while being in direct contact with a filter tow. The shaping paper is used to, when a plurality of filter sections wrapped with the filter wrapper is present, fix the plurality of filter sections. The tipping paper is used to join the tobacco rod portion and the filter portion to each other.

Such a filter wrapping paper can be made of a publicly known material.

When a granular activated carbon described later is added to the filter portion of the smoking product according to the present invention, the filter portion is used in a form in which a plurality of filter sections is connected to each other using a shaping paper, and is generally joined to the tobacco rod portion using a tipping paper. Usually, the most downstream filter section, held in a user's mouth, of the filter portion including a plurality of filter sections is preferably a white acetate tow-filled filter section to which a granular activated carbon is not added from the viewpoint of appearance.

An example of the form in which a plurality of filter sections is connected to each other using a shaping paper is a form in which two filter sections are fixed using a shaping paper with a space therebetween and the space is filled with a granular activated carbon described later. In this form, the amount of granular activated carbon added per filter length can be increased compared with the form in which a granular activated carbon is added to the filter sections.

<Granular Activated Carbon>

The filter portion of the smoking product according to the present invention includes a granular activated carbon.

Activated carbon refers to a substance that is mainly composed of porous carbon that has been subjected to chemical or physical treatment (activation) to increase the adsorption efficacy for the purpose of, for example, selectively separating, removing, or purifying a particular substance.

The activated carbon included in the filter portion of the smoking product according to the present invention is a granular activated carbon, which is a collective term for a pulverized carbon having a particle size of 150 μm or more.

The particle size of the granular activated carbon included in the filter portion of the smoking product according to the present invention can be changed in accordance with the required performance and the filter structure.

The particle size of the granular activated carbon is preferably 150 μm or more and 2000 μm or less, more preferably 160 μ or more and 850 μm or less, further preferably 180 μm or more and 600 μm or more, and particularly preferably 212 μm or more and 425 μm or less.

When the particle size of the granular activated carbon is within the above range, the inside of a cylinder having a circumference of about 16.8 mm to 25.8 mm, which is a typical size of a filter portion for cigarettes, can be relatively uniformly filled with the granular activated carbon.

If the granular activated carbon has a particle size of more than 2000 μm, the weight of a granular activated carbon added to the filter portion may vary between tobacco rods.

If the granular activated carbon has a particle size of less than 150 μm, dust of activated carbon is generated during the production of the filter portion including a granular activated carbon, which contaminates the production apparatus and complicates the cleaning process. Furthermore, when a filter portion to which a granular activated carbon is not added is produced using the same production apparatus, the filter portion may be contaminated.

The particle size of the granular activated carbon can be adjusted in accordance with the pulverizing method of a granular activated carbon and the pulverizing time. Alternatively, the particle size can be adjusted in accordance with the opening of a sieve used in a sieving process of the granular activated carbon.

The amount of a granular activated carbon added to the filter portion of the smoking product according to the present invention is not particularly limited, but is preferably 10 to 200 mg per filter length 10 mm (filter circumference: about 16.8 mm to 25.8 mm).

<Raw Material for Granular Activated Carbon>

For the granular activated carbon included in the filter portion of the smoking product according to the present invention, a granular coconut shell activated carbon made of coconut shell charcoal is used from the viewpoint of high adsorption efficacy for volatile organic substances in tobacco smoke and low influence on smoke flavor and taste.

<Method for Activating Granular Activated Carbon>

The granular activated carbon included in the filter portion of the smoking product according to the present invention is preferably activated by a gas activation method from the viewpoint of relatively easily achieving scale-up and providing a high-purity granular activated carbon.

Examples of gas used in the gas activation method include oxidizing gases such as water vapor, carbon dioxide, and air. The granular activated carbon included in the filter portion of the smoking product according to the present invention is generally activated using water vapor.

The activation temperature in the gas activation method is normally in the range of 750° C. or higher and 1000° C. or lower and can be changed in accordance with the intended lightness, color difference, and acetone adsorption capacity of the granular activated carbon. In general, when the activation temperature increases, the lightness and the color difference decrease and the acetone adsorption capacity improves.

The activation time in the gas activation method is dependent on the type of gas activation apparatus used, and is generally in the range of 0.5 hours or longer and 30 hours or shorter. The activation time can be changed in accordance with the intended lightness, color difference, and acetone adsorption capacity of the granular activated carbon. In general, when the activation time increases, the lightness and the color difference decrease and the acetone adsorption capacity improves.

The granular activated carbon included in the filter portion of the smoking product according to the present invention can be activated in an apparatus typically used in the gas activation method, such as a rotary kiln or a fluidized-bed activation furnace. Among these apparatuses, a fluidized-bed activation furnace is preferably used because a granular activated carbon having a lightness and a color difference within particular numerical ranges described later is easily provided.

<Adsorption Capacity of Granular Activated Carbon>

The acetone adsorption capacity of the granular activated carbon included in the filter portion of the smoking product according to the present invention is 29.0% or more and 41.0% or less in terms of mass fraction.

The acetone adsorption capacity of the granular activated carbon is measured in conformity with JIS K 1474.

If the lower limit of the acetone adsorption capacity of the granular activated carbon is less than 29.0% in terms of mass fraction, the lightness L* and the color difference ΔE of the granular activated carbon will be outside the particular numerical ranges described later. Consequently, the granular activated carbon cannot be used for determining the authenticity of smoking products.

If the upper limit of the acetone adsorption capacity of the granular activated carbon is more than 41.0% in terms of mass fraction, the granular activated carbon embrittles, which may cause contamination of the filter portion due to pieces or the like of the granular activated carbon when the granular activated carbon is added to the filter portion.

The acetone adsorption capacity of the granular activated carbon is preferably 29.0% or more and 40.0% or less, more preferably 30.0% or more and 40.0% or less, and further preferably 33.0% or more and 38.0% or less in terms of mass fraction.

The acetone adsorption capacity of the granular activated carbon can be controlled by the method for activating a granular activated carbon or in accordance with the degree of activation adjusted by the activation temperature and the activation time.

<Lightness of Granular Activated Carbon>

The lightness L* in the CIE Lab colorimetric system of the granular activated carbon included in the filter portion of the smoking product according to the present invention is 11.50 or more and 19.00 or less.

The lightness L* of the granular activated carbon is preferably 12.00 or more and 18.00 or less, more preferably 12.00 or more and 17.50 or less, and further preferably 12.00 or more and 13.50 or less.

When the lightness L* of the granular activated carbon is within the above range, the granular activated carbon can be used for determining the authenticity of smoking products while an acetone adsorption capacity higher than or equal to that of known granular activated carbons is achieved. Furthermore, a change in specifications of the granular activated carbon is not easily recognized by users.

If the lower limit of the lightness L* of the granular activated carbon is less than 11.50, the granular activated carbon embrittles, which may cause contamination of the filter portion due to pieces or the like of the granular activated carbon when the granular activated carbon is added to the filter portion.

If the upper limit of the lightness L* of the granular activated carbon is more than 19.00, the granular activated carbon cannot be used for determining the authenticity of smoking products, and an acetone adsorption capacity higher than or equal to that of known granular activated carbons cannot be achieved.

The lightness L* of the granular activated carbon can be controlled by the method for activating a granular activated carbon or in accordance with the degree of activation adjusted by the activation temperature and the activation time.

<Color Difference of Granular Activated Carbon>

The color difference ΔE in the CIE Lab colorimetric system of the granular activated carbon included in the filter portion of the smoking product according to the present invention is a value calculated on the basis of the blank lightness L* and chromaticities a* and b* described later.

The color difference ΔE in the CIE Lab colorimetric system of the granular activated carbon included in the filter portion of the smoking product according to the present invention is preferably 14.00 or more and 21.50 or less, more preferably 14.50 or more and 20.50 or less, further preferably 14.50 or more and 20.00 or less, and particularly preferably 14.50 or more and 16.00 or less.

When the color difference ΔE of the granular activated carbon is within the above range, the granular activated carbon can be used for determining the authenticity of smoking products while an acetone adsorption capacity higher than or equal to that of known granular activated carbons is achieved. Furthermore, a change in specifications of the granular activated carbon is not easily recognized by users.

The color difference ΔE of the granular activated carbon can be controlled by the method for activating a granular activated carbon or in accordance with the degree of activation adjusted by the activation temperature and the activation time.

In the above ranges of the lightness L* and the like, the authenticity of smoking products can be determined. Therefore, the granular activated carbon included in the filter portion of the smoking product according to the present invention does not require coloring performed in the prior art.

<Production of Smoking Product According to the Present Invention>

The method for producing a smoking product according to the present invention may employ a process including publicly known steps, except for a step of providing a granular activated carbon having a lightness L* in a particular numerical range or a step of providing a granular activated carbon having a lightness L* and a color difference ΔE in particular numerical ranges.

For example, the method includes at least one of a step of wrapping shredded tobacco with a wrapping paper using an existing technique, a step of performing cutting to a length of a single smoking product to produce a tobacco rod portion, and a step of joining a tobacco rod portion to both ends of a filter portion for two smoking products and performing wrapping with a tipping paper for two smoking products. The method further optionally includes, after the above step, a step of performing cutting to a length of a single smoking product at the center in the longitudinal direction to produce two smoking products.

The tobacco leaf raw material that is a raw material for shredded tobacco or the like included in the tobacco rod portion may be the same as the above-described tobacco leaf raw material. That is, the tobacco leaf raw material may be a shredded tobacco leaf raw material or an unshredded tobacco leaf raw material. For the tobacco leaf raw material, either a mesophyll portion (lamina) or a vein portion (midrib) obtained by separating tobacco leaves may be used, or a tobacco stem portion that is not a tobacco leaf portion may be contained. The tobacco leaf raw material may be a raw material shredded so as to have a shredding width of 0.1 to 2.0 mm. The tobacco leaf varieties may be main varieties such as yellow varieties, burley varieties, native varieties, and orient varieties, or fermented leaves using the foregoing.

In the production of a filter portion including a granular activated carbon, publicly known steps can also be employed in combination.

For example, when a paper sheet is used as a filter material, the following steps can be appropriately combined: a step of adding a granular activated carbon that has a particular lightness or a particular lightness and color difference and that is sorted in a process described later to the paper sheet from above by an addition mechanism, a step of folding the paper sheet in a trumpet portion of a filter wrapping machine into a cylindrical shape having a certain diameter and wrapping the folded paper sheet with a filter wrapper, and a step of performing cutting to a certain length to produce a filter portion.

When acetate tow is used as a filter material, for example, the following steps can be appropriately combined: a step of spreading acetate tow and optionally adding, for example, triacetylene as a plasticizer for the acetate tow; a step of adding a granular activated carbon having a particular lightness or a particular lightness and color difference and sorted in a process described later by an addition mechanism, then performing bundling to a certain diameter, and performing wrapping with a filter wrapper; and a step of performing cutting to a certain length to produce a filter portion.

When applied to smoking products, any of the filter portions produced through the above process and including a granular activated carbon is used in a form in which a plurality of filter sections are connected to each other using a shaping paper, and generally joined to the tobacco rod portion using a tipping paper. Normally, the most downstream filter section, held in a user's mouth, of the filter portion including a plurality of filter sections is preferably a white acetate tow-filled filter section to which a granular activated carbon is not added from the viewpoint of appearance.

An example of the form in which a plurality of filter sections is connected to each other using a shaping paper is a form in which two filter sections are fixed using a shaping paper with a space therebetween and the space is filled with a granular activated carbon. In this form, the amount of a granular activated carbon added per filter length can be increased compared with the form in which a granular activated carbon is added to the filter sections formed of a paper sheet or acetate tow.

The amount of a granular activated carbon added to the filter portion is not particularly limited, but is preferably 10 to 200 mg per filter length 10 mm (filter circumference: about 16.8 mm to 25.8 mm).

The method for producing a smoking product according to the present invention includes a step of providing a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less in the CIE Lab colorimetric system.

The step of providing a granular activated carbon includes a step of numerically expressing a color of a granular activated carbon in the CIE Lab colorimetric system and a step of sorting, as a granular activated carbon added to a filter portion of a smoking product, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less from the granular activated carbons having a numerically expressed color.

The step of numerically expressing a color of a granular activated carbon in the CIE Lab colorimetric system is a step of numerically expressing a color by measuring the lightness L*, chromaticity a*, and chromaticity b* of the granular activated carbon in the CIE Lab colorimetric system in conformity with JIS K 8730 using a colorimeter (e.g., SM-T45 manufactured by Suga Test Instruments Co., Ltd.). The granular activated carbon sample to be measured is preferably prepared in conformity with JIS K 7373.

In the step of sorting, as a granular activated carbon added to a filter portion of a smoking product, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less, the lightness L* is preferably 12.00 or more and 18.00 or less, more preferably 12.00 or more and 17.50 or less, and further preferably 12.00 or more and 13.50 or less.

In the step of sorting a granular activated carbon as a granular activated carbon added to a filter portion of a smoking product, the process is not particularly limited as long as a granular activated carbon having a lightness L* within the above range and a granular activated carbon having a lightness L* outside the above range can be separated from each other.

The method for producing a smoking product according to the present invention may include a step of providing a granular activated carbon that has a lightness L* of 11.50 or more and 19.00 or less in the CIE Lab colorimetric system and that also has a color difference ΔE of 14.00 or more and 21.50 or less in the CIE Lab colorimetric system.

The step of providing a granular activated carbon includes a step of numerically expressing a color of a granular activated carbon in the CIE Lab colorimetric system and a step of sorting, as a granular activated carbon added to a filter portion of a smoking product, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less from the granular activated carbons having a numerically expressed color.

The step of numerically expressing a color of a granular activated carbon in the CIE Lab colorimetric system includes a step of numerically expressing a color by measuring the lightness L*, chromaticity a*, and chromaticity b* of the granular activated carbon and the blank in the CIE Lab colorimetric system in conformity with JIS K 8730 using a colorimeter (e.g., SM-T45 manufactured by Suga Test Instruments Co., Ltd.) and a step of calculating the color difference ΔE of the granular activated carbon from the obtained lightness L*, chromaticity a*, and chromaticity b* in conformity with JIS K 8730. The granular activated carbon sample to be measured is preferably prepared in conformity with JIS K 7373.

In the step of sorting, as a granular activated carbon added to a filter portion of a smoking product, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less, the lightness L* is preferably 12.00 or more and 18.00 or less, more preferably 12.00 or more and 17.50 or less, and further preferably 12.00 or more and 13.50 or less. The color difference ΔE is preferably 14.50 or more and 20.50 or less, more preferably 14.50 or more and 20.00 or less, and further preferably 14.50 or more and 16.00 or less.

In the step of sorting a granular activated carbon as a granular activated carbon added to a filter portion of a smoking product, the process is not particularly limited as long as a granular activated carbon having a lightness L* and a color difference ΔE within the above ranges and a granular activated carbon having a lightness L* and a color difference ΔE outside the above ranges can be separated from each other.

The method for producing a smoking product according to the present invention includes a step of adding, to a filter portion through the above-described publicly known step, the granular activated carbon that has a lightness L* in the CIE Lab colorimetric system within the above range and that has been provided in the step of providing a granular activated carbon.

Alternatively, the method for producing a smoking product according to the present invention may include a step of adding, to a filter portion through the above-described publicly known step, the granular activated carbon that has a lightness L* and a color difference ΔE in the CIE Lab colorimetric system within the above ranges and that has been provided in the step of providing a granular activated carbon.

When the method for producing a smoking product according to the present invention includes the above-described step of providing a granular activated carbon, a smoking product including, in a filter portion, a granular activated carbon that has an acetone adsorption capacity higher than or equal to that of known granular activated carbons and that allows determination of the authenticity of smoking products based on color can be produced. In the method for producing a smoking product according to the present invention, a granular activated carbon having a particular lightness L* and the like is used as described above, which does not require processing such as coloring of the granular activated carbon.

<Method for Distinguishing Granular Activated Carbon>

The method for distinguishing a granular activated carbon added to a smoking product filter according to the present invention includes a step of numerically expressing a color of the granular activated carbon in the CIE Lab colorimetric system and a step of sorting, as a granular activated carbon added to a smoking product filter, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less in the CIE Lab colorimetric system.

The step of numerically expressing a color of the granular activated carbon in the CIE Lab colorimetric system is a step of numerically expressing a color by measuring the lightness L*, chromaticity a*, and chromaticity b* of the granular activated carbon in the CIE Lab colorimetric system in conformity with JIS K 8730 using a colorimeter (e.g., SM-T45 manufactured by Suga Test Instruments Co., Ltd.). The granular activated carbon sample to be measured is preferably prepared in conformity with JIS K 7373.

In the step of sorting, as a granular activated carbon added to a filter portion of a smoking product, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less, the lightness L* is preferably 12.00 or more and 18.00 or less, more preferably 12.00 or more and 17.50 or less, and further preferably 12.00 or more and 13.50 or less.

In the sorting step, the sorting process is not particularly limited as long as a granular activated carbon having a lightness L* within the above range and a granular activated carbon having a lightness L* outside the above range can be separated from each other.

The method for distinguishing a granular activated carbon added to a smoking product filter according to the present invention may include a step of sorting, as a granular activated carbon added to a smoking product filter, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less in the CIE Lab colorimetric system.

The step of sorting a granular activated carbon as a granular activated carbon added to a filter portion of a smoking product includes a step of numerically expressing a color by measuring the lightness L*, chromaticity a*, and chromaticity b* of the granular activated carbon and the blank in the CIE Lab colorimetric system in conformity with JIS K 8730 using a colorimeter (e.g., SM-T45 manufactured by Suga Test Instruments Co., Ltd.) and a step of calculating the color difference ΔE of the granular activated carbon from the obtained lightness L*, chromaticity a*, and chromaticity b* in conformity with JIS K 8730. The granular activated carbon sample to be measured is preferably prepared in conformity with JIS K 7373.

In the step of sorting, as a granular activated carbon added to a smoking product filter, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less, the lightness L* is preferably 12.00 or more and 18.00 or less, more preferably 12.00 or more and 17.50 or less, and further preferably 12.00 or more and 13.50 or less. The color difference ΔE is preferably 14.50 or more and 20.50 or less, more preferably 14.50 or more and 20.00 or less, and further preferably 14.50 or more and 16.00 or less.

In the sorting step, the sorting process is not particularly limited as long as a granular activated carbon having a lightness L* and a color difference ΔE within the above ranges and a granular activated carbon having a lightness L* and a color difference ΔE outside the above ranges can be separated from each other.

According to the method for distinguishing a granular activated carbon added to a smoking product filter according to the present invention, a granular activated carbon that has an acetone adsorption capacity higher than or equal to that of known granular activated carbons and that is advantageous for determining the authenticity of smoking products based on color can be objectively sorted without subjectivity.

EXAMPLES

The present invention will be further specifically described based on Examples, but is not limited to Examples below within the spirit of the present invention.

<1. Preparation of Sample>

For samples used in Examples and Comparative Examples, Kuraray Co., Ltd. was asked to produce prototypes under the following conditions, and the produced prototypes were purchased from Kuraray Co., Ltd.

First, the raw material for each of the samples in all Examples and Comparative Examples was a coarsely pulverized coconut shell charcoal before activation treatment, which is used to produce a granular coconut shell activated carbon “KURARAY COAL (registered trademark) GGS-N28/70” available from Kuraray Co., Ltd.

(Sample in Comparative Example 3)

In Comparative Example 3, the above-described commercially available granular coconut shell activated carbon “KURARAY COAL (registered trademark) GGS-N28/70” itself was used as a sample.

The acetone adsorption capacity (catalog value) of the granular coconut shell activated carbon is 25±2% in terms of mass fraction.

(Sample in Comparative Example 1)

In Comparative Example 1, a granular coconut shell charcoal obtained by performing pulverizing and sieving treatment so as to have the same particle size distribution as in Comparative Example 3 without performing activation treatment on a coarsely pulverized coconut shell charcoal serving as a raw material was used as a sample.

The pulverizing and sieving treatment is the same as the pulverizing and sieving treatment performed on the above-described commercially available granular coconut shell activated carbon “KURARAY COAL (registered trademark) GGS-N28/70”.

For all the samples in Examples and Comparative Examples described hereafter, the particle size distribution was adjusted by performing the pulverizing and sieving treatment so as to be the same particle size distribution as in Comparative Example 3.

(Sample in Comparative Example 2)

In Comparative Example 2, activation treatment was performed on a coarsely pulverized coconut shell charcoal serving as a raw material using an apparatus that is the same as the fluidized-bed activation furnace used for activating the above-described commercially available granular coconut shell activated carbon “KURARAY COAL (registered trademark) GGS-N28/70”. The obtained granular coconut shell activated carbon was used as a sample. In this activation treatment, the activation treatment time was mainly shortened so that the degree of the activation treatment was lower than that of activation treatment performed on the above-described commercially available granular coconut shell activated carbon, thereby controlling the acetone adsorption capacity of the obtained granular coconut shell activated carbon to about 19% in terms of mass fraction.

The activation treatment performed to produce the samples in Examples 1 to 4 described hereafter was also performed using an apparatus that is the same as the fluidized-bed activation furnace used for activating the above-described commercially available granular coconut shell activated carbon “KURARAY COAL (registered trademark) GGS-N28/70”.

(Sample in Example 1)

A coarsely pulverized coconut shell charcoal serving as a raw material was activated with the fluidized-bed activation furnace. The obtained granular coconut shell activated carbon was used as a sample. In this activation treatment, the activation treatment time was mainly lengthened so that the degree of the activation treatment was higher than that of activation treatment performed on the above-described commercially available granular coconut shell activated carbon, thereby controlling the acetone adsorption capacity of the obtained granular coconut shell activated carbon to about 28% in terms of mass fraction.

(Sample in Example 2)

A coarsely pulverized coconut shell charcoal serving as a raw material was activated with the fluidized-bed activation furnace. The obtained granular coconut shell activated carbon was used as a sample. In this activation treatment, the activation treatment time was mainly lengthened so that the degree of the activation treatment was higher than that of activation treatment in Example 1, thereby controlling the acetone adsorption capacity of the obtained granular coconut shell activated carbon to about 37% in terms of mass fraction.

(Sample in Example 3)

A coarsely pulverized coconut shell charcoal serving as a raw material was activated with the fluidized-bed activation furnace. The obtained granular coconut shell activated carbon was used as a sample. In this activation treatment, the activation treatment time was mainly lengthened so that the degree of the activation treatment was higher than that of activation treatment in Example 2, thereby controlling the acetone adsorption capacity of the obtained granular coconut shell activated carbon to about 40% in terms of mass fraction.

(Sample in Example 4)

A coarsely pulverized coconut shell charcoal serving as a raw material was activated with the fluidized-bed activation furnace. The obtained granular coconut shell activated carbon was used as a sample. In this activation treatment, the activation treatment time was mainly lengthened so that the degree of the activation treatment was higher than that of activation treatment in Example 3, thereby controlling the acetone adsorption capacity of the obtained granular coconut shell activated carbon to a value higher than that in Example 3 (if possible, about 45% in terms of mass fraction).

(Sample in Comparative Example 4)

A coarsely pulverized coconut shell charcoal serving as a raw material was activated with a rotary kiln. The obtained granular coconut shell activated carbon was used as a sample. This activation treatment was performed so that the acetone adsorption capacity of the obtained granular coconut shell activated carbon was substantially equal to that in Comparative Example 3.

<2. Measurement of Lightness L*, Chromaticity and Chromaticity b*, and Calculation of Color Difference ΔE>

The lightness L*, chromaticity a*, and chromaticity b* of the granular coconut shell activated carbons in Examples 1 to 4 and Comparative Examples 1 to 4 were measured by the following method.

The above-described one granular coconut shell charcoal and seven granular coconut shell activated carbons themselves were used as test samples in conformity with JIS K 7373. A quartz cell (material: synthetic quartz glass, optical path length×optical path width: 10×10 mm) with a screw cap was filled with each of the test samples.

Each of the samples (Comparative Examples 1 to 4 and Examples 1 to 4) with which the quartz cell was filled was measured in conformity with JIS Z 8730 using a tristimulus colorimeter (SM-T45 manufactured by Suga Test Instruments Co., Ltd.). The reflection measurement was employed, and the optical conditions were 45° lighting-0° light receiving (45°:0°). The measurements were performed three times for each of the samples, and the average of the measured values was used as a value of the measurement results. For the blank, the measurement was performed once using only a quartz cell with which the sample was not filled.

The color difference ΔE of the granular coconut shell activated carbon was calculated from formula (I) below in conformity with JIS Z 8730.

ΔE={(ΔL*)²+(Δa*)²+(Δb*)²}^(1/2)   (I)

Herein, ΔL* represents a difference between the lightness L* of each sample and the lightness L* of the blank, Δa* represents a difference between the chromaticity a* of each sample and the chromaticity a* of the blank, and Δb* represents a difference between the chromaticity b* of each sample and the chromaticity b* of the blank.

Table 1 shows the measured lightness L*, chromaticity a*, and chromaticity b* of the granular coconut shell charcoal in Comparative Example 1 and the granular coconut shell activated carbons in Comparative Examples 2 to 4 and Examples 1 to 4 and the calculated color difference ΔE.

TABLE 1 L* a* b* ΔE Blank −2.39 −0.86 −0.83 — Comparative 22.73 −0.10  0.44 25.17 Example 1 Comparative 22.19  0.11  1.22 24.69 Example 2 Comparative 19.07  0.21  0.93 21.56 Example 3 Example 1 17.64  0.30  0.83 20.14 Example 2 12.41  0.26  0.51 14.90 Example 3 11.96  0.12  0.21 14.43 Example 4 13.65  0.00  0.60 16.13 Comparative 22.21  0.17  0.84 24.68 Example 4

<3. Measurement of Acetone Adsorption Capacity>

The acetone adsorption capacity of the granular activated carbon was measured in conformity with JIS K 1474.

The granular coconut shell activated carbons of the same lot as those used in <2. Measurement of lightness L*, chromaticity and chromaticity b*, and calculation of color difference ΔE> were used as granular activated carbons, except for the granular coconut shell activated carbon in Comparative Example 4.

Table 2 shows the measurement results of the acetone adsorption capacity of the granular coconut shell activated carbons in Comparative Examples 1 to 3 and Examples 1 to 4.

TABLE 2 Acetone adsorption capacity (% in terms of mass fraction) Comparative  3.2 Example 1 Comparative 19.1 Example 2 Comparative 23.8 Example 3 Example 1 29.1 Example 2 36.5 Example 3 40.2 Example 4 39.2

<4. Investigation for Distinguishing by Visual Observation>

Fifty panelists investigated whether two different granular activated carbons could be visually distinguished. The investigation method is as follows.

The granular coconut shell activated carbons of the same lot as those used in <3. Measurement of acetone adsorption capacity> were used as granular activated carbons.

The granular coconut shell activated carbons in Comparative Examples 1 to 3 and Examples 1 to 4 were each encapsulated in a 40 ml transparent vial, and handed to the panelists as seven samples.

The panelists determined whether two different samples could be distinguished by using one sample as a reference and visually observing the other six samples.

The visual observation was performed by a method in which the encapsulated granular coconut shell activated carbon was observed through the transparent vial, and was then taken out from the vial, placed on a desk, and directly observed.

From the overall results of the visual observation, the panelists determined whether two different samples could be distinguished based on all combinations of the seven samples. The combinations of distinguishable samples were recorded.

The combinations of distinguishable samples recorded by the panelists through visual observation were totalized. Table 3 shows the results in units of percentage.

TABLE 3 Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 4 Comparative 0 0 70 100 100 100 Example 1 Comparative 0 62 100 100 100 Example 2 Comparative 52 100 100 100 Example 3 Example 1 24 48 36 Example 2 0 0 Example 3 0 Example 4

The numerical values in Table 3 are the percentage of the number of panelists that have determined the sample to be distinguishable through visual observation.

Table 3 shows that the samples in Comparative Examples 1 to 3 cannot be distinguished from each other.

Table 3 also shows that the samples in Examples 2 to 4 cannot be distinguished from each other.

50% or more of the panelists determined Example 1 to be distinguishable from the samples in Comparative Examples 1 to 3 whereas less than 50% of the panelists determined Example 1 to be distinguishable from the samples in Examples 2 to 4. Therefore, in the case of visual observation, the particles of the granular coconut shell activated carbon of Example 1 are closer to those in Examples 2 to 4.

Accordingly, when the granular coconut shell activated carbons in Comparative Examples 1 to 3 are unauthorized products and the granular coconut shell activated carbons in Examples 1 to 4 are authorized products, both of them can be distinguished from each other through visual observation. Therefore, the authenticity of smoking products can be determined by using the granular activated carbon included in the filter portion. 

What is claimed is:
 1. A smoking product comprising a tobacco rod portion and a filter portion including a granular activated carbon, wherein the granular activated carbon has a lightness L* of 11.50 or more and 19.00 or less in a CIE Lab colorimetric system and an acetone adsorption capacity of 29.0% or more and 41.0% or less in terms of mass fraction.
 2. The smoking product according to claim 1, wherein the granular activated carbon has a color difference ΔE of 14.00 or more and 21.50 or less in the CIE Lab colorimetric system.
 3. The smoking product according to claim 1, wherein the granular activated carbon is a granular coconut shell activated carbon.
 4. A method for producing a smoking product comprising a tobacco rod portion and a filter portion including a granular activated carbon, the method comprising a step of providing a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less in a CIE Lab colorimetric system and a step of adding the provided granular activated carbon to the filter portion.
 5. The method for producing a smoking product according to claim 4, wherein in the providing step, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less in the CIE Lab colorimetric system is provided.
 6. The method for producing a smoking product according to claim 4, wherein the granular activated carbon has an acetone adsorption capacity of 29.0% or more and 41.0% or less in terms of mass fraction.
 7. The method for producing a smoking product according to claim 4, wherein the granular activated carbon is a granular coconut shell activated carbon.
 8. A method for distinguishing a granular activated carbon added to a smoking product filter, the method comprising: a step of numerically expressing a color of the granular activated carbon in a CIE Lab colorimetric system; and a step of sorting, as the granular activated carbon added to the smoking product filter, a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less in the CIE Lab colorimetric system.
 9. The method according to claim 8, wherein the step of sorting includes a step of sorting a granular activated carbon having a lightness L* of 11.50 or more and 19.00 or less and also having a color difference ΔE of 14.00 or more and 21.50 or less in the CIE Lab colorimetric system. 